The present invention relates to tracks for vehicles. More particularly, the present invention relates to a track-switching apparatus and a method for switching tracks.
Since the early twentieth century, controlling the movement of vehicles that reside on tracks such as trains, intrafactory cargo vehicles, and amusement park rides has lead to important industrial growth and consumer satisfaction. In the case of amusement parks, as guests have demanded bigger, better, and more elaborate rides, they also require and expect a positive park experience, which entails progressively shorter and more rapidly moving lines to enter a ride.
One technique to shorten wait times for lines involves increasing the throughput of vehicles on a track. The more vehicles that pass a given point on a track in a given time interval, the more guests are capable of being served. However, in rides that have multiple tracks and require vehicles to switch tracks, there exists a lag or delay for the track-switch to take place. Decreasing the delay for track-switching increases vehicle throughput, thereby shortening guest wait time, and as a consequence, increases guest satisfaction and park profits.
In the past, conventional track-switching has been accomplished through the use of a pair of linked tapering rails, known as points, disposed between diverging outer rails. The points can be moved laterally from one position to another to direct a vehicle to a diverging track from a through track through the use of gear boxes, slide bars or motors. For example, U.S. Pat. No. 5,547,151 employs a linear induction rail switch mechanism having at least one linear induction motor for transversely thrusting a switch track from a first position to a second position.
More current track-switching mechanisms include spring assemblies such as that of U.S. Pat. No. 6,290,189, which describes a point-operating device for pressing a tongue against a stock rail while simultaneously pulling off another tongue from an opposite stock rail. The device is formed with at least four adjustable vertical spring assemblies, and is meant to prevent tongue hang-up.
However, known track-switching devices such as those mentioned above typically require a response time that may not meet the desired response time in some applications, such as amusement park settings, and are restricted to rail applications where the principal wheel assembly rides on a single side of the track, and lateral guidance is provided by a flange on the wheel.
In modern theme park attractions, such as roller-coasters, it is often necessary to have lateral guide wheels and vertical guide wheels on both the upper surface (i.e., load wheels) and lower surface (i.e., upstop wheels) of the track so that the ride vehicle is fully constrained to the track in all directions (save the desired direction of travel). These features substantially limit the utility of the aforementioned one-sided track switch assemblies
Conventional track switches for theme park attraction applications generally comprise configurations that move laterally, rotationally about a vertical axis, and rotationally about a longitudinal axis, and involve separate locking and driving mechanisms. The driving mechanisms may be linked to the track switch assembly via conventional power transmission features, such as belts, drive shafts, chains, and gear trains. As such, the inertia of the drive mechanism and the switch assembly is always coupled to the mechanical system, providing practical limits to the combined acceleration and positioning accuracy of said switch types. Switching mechanisms similar to those discussed above may be found in, for example, U.S. Pat. No. 4,543,886 to Intamin Inc. and U.S. Pat. No. 6,884,177 to Vekoma S.p.A.
Manufactures have increasingly employed more powerful primary drive devices for switches that yield diminishing returns, as the self-inertia of larger and larger (e.g., electric) motors presents a first-order effect that defines the torque/horsepower/speed rise-time curve, particularly when the physical size and packaging of such devices is considered, this last resulting in necessarily causing such devices to be remote from the switched device, further increasing inertia and attendant switch timing delay.
Accordingly, to date, no suitable apparatus or method for rapid track-switching is available.